The present invention relates to an industrial robot device including a robot and a processing machine. such as a lathe, a welding machine or the like. More particularly. the invention relates to an industrial robot device capable of making the coordinates of the actual movement of the robot or the absolute coordinates of the software programmed for the driving of the robot coincide with the absolute coordinates of the processing device, so that the robot can be accurately operated with respect to the reference planes of the processing machine, in accordance with processing instructions input by an offline-teaching method such as MDI (Manual Data Input). The MDI operations involve the entering of values for the directions of the X, Y and Z axes with respect to the robot and the X. Y and Z dimensions, and moving the robot to the required positions.
FIG. 1 is a diagram illustrating the relation between the coordinates of two points with respect to the X, Y and Z reference planes of the processing machine (such as a lathe or a welding machine) and the coordinates of the locus of the tip of the arm of the robot which is actuated by offline-teaching of the coordinates of these two points. At 21 is a segment joining the coordinates (X.sub.a, Y.sub.a, Z.sub.a) and coordinates (X.sub.b, Y.sub.b, Z.sub.b) of the points a and b taken with respect to the X. Y and Z reference planes of the processing machine at the work station. At 22 is the robot arm tip locus which results from actuation in accordance with a processing instruction. taken in relation to the coordinates of the two points and b, and which joins the coordinates A (X.sub.A, Y.sub.A, Z.sub.A) and B (X.sub.B, Y.sub.B, Z.sub.B). The "deviation" between the coordinates a and A. and b and B may occur due to errors in manufacturing the robot. More specifically, a manufacturing error in the arm length of the robot and/or an error in alignment between the robot and the processing machine may result in such a "deviation".
Assuming that the "deviation" between the two sets of coordinates a and b of the two points and those A and B occurs, if direct teaching relative to the processing machine is not effected but rather the processing instructions are input by the above-mentioned MDI operation, the robot arm tip which is driven via the control unit, etc. on the basis of this processing instruction, moves according to the coordinates of the processing machine, which deviate from the absolute coordinates. It is therefore not possible to carry out processing that is faithful to the processing instructions, input by an offline-teaching procedure such as the above-noted MDI operation.
Further, in the conventional robot, the programmed software's absolute X, Y and Z axes are set in specific directions with respect to the robot. In an industrial robot device including such a conventional robot, the MDI operation is effective if the robot body is installed with the programmed software's absolute X, Y and Z axes accurately matching the X, Y and Z axes of the processing machine such as the lathe or similar processing machine, (See for example, Published Examined Japanese Patent Application No. 55-21362).
In this case, however, since the directions of the programmed software s absolute X, Y and Z axes are generally not indicated on the robot body, in order to actuate the robot via the MDI operation, reference surfaces which are accurately adjusted to the programmed software's absolute X, Y and Z axes are required to be installed at the base of the robot. However, it is likely that due to errors in manufacturing the robot, it will not be easy to adjust the reference surfaces accurately relative to the programmed software's absolute X, Y and Z axes.